The typical driver side air bag module comprises a base plate, an inflator, an air bag and a cover. The base plate is mounted at or near the hub of the steering wheel; the inflator and air bag are located within the base plate and the cover protects the air bag. As the air bag inflates, the cover is broken apart thereby permitting the inflating air bag to expand. As can be appreciated, because the cover is a sacrificial part of the module it cannot be used to support permanent buttons, displays, switches and the like.
Another characteristic of the prior art construction is that on deployment, the expanding air bag is initially thrust directly toward the occupant, which may increase the level of forceful interference between the occupant and the expanding air bag. To restrict this forward motion, many prior art systems have resorted to the use of tethers, which attempt to control the trajectory of the expanding air bag.
It is an object of the present invention to provide an air bag module with a center control module that is fixed in relationship to the steering wheel and one in which the air bag and cover deploy about this fixed center control module. Consequently, an advantage of this construction is the fixed center control module can now support control or communication mechanisms and devices such as a horn switch, radio dials, cruise control buttons and even more complicated and expensive visual displays for a navigation system, including GPS satellite receiver display. These additional mechanisms and devices will be somewhat protected by the deployment of the air bag and may not need to be repaired when a new air bag module is installed or they can be reused in replacement air bag modules. In addition, this construction allows for additional or replacement mechanisms to be installed in the air bag module before it is deployed.
Another object of the invention is to provide a module in which the air bag is encouraged to initially fill radially due in part to the fixed center control module. Accordingly the invention comprises an air bag module having a base plate and a toroidal air bag defining an inner chamber. The toroidal air bag is coupled to the base plate. A control module having a base plate portion and a generally cylindrical portion is coupled to the base. The control module has a control module cover coupled to said generally cylindrical portion disposed within said inner chamber.
Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.